CN109085111B - Active double-piston type ventilation rate standard rod calibration device and calibration method thereof - Google Patents

Abstract

The invention discloses an active double-piston type ventilation rate standard rod calibration device and a calibration method. The dual-piston type flow standard device driven by the stepping motor is adopted, the first piston and the second piston synchronously and coordinately run, and the calibration of the ventilation rate standard rod can be realized.

Description

An active dual-piston ventilation rate standard rod calibration device and calibration method thereof

technical field

The invention belongs to the technical field of calibration of standard parts of cigarette testing instruments, and in particular relates to an active double-piston ventilation rate standard bar calibration device and a calibration method.

Background technique

Filter ventilation technology is currently a means of tar reduction and harm reduction widely adopted by cigarette industry enterprises at home and abroad. The ventilation rate is directly related to the mainstream smoke emission and sensory quality of cigarettes. Generally speaking, the greater the cigarette ventilation rate, the lower the tar release rate, and the cigarette ventilation rate is one of the physical parameters strictly controlled by the cigarette factory.

The ventilation rate standard rod is a standard part used in conjunction with the cigarette ventilation rate measuring instrument. The ventilation rate standard rod transmits the accurate value to the ventilation rate measuring instrument, and the ventilation rate measuring instrument transmits the value to the cigarette. The accuracy of the ventilation rate standard rod directly determines the reliability of the ventilation rate measurement data of the cigarette. In the process of using ventilation rate standard rods in the cigarette testing department, environmental factors, human factors, calibration factors, material factors, etc. will cause the value of ventilation rate standard rods to deviate, resulting in poor reliability of cigarette ventilation rate parameter measurement data. Therefore, the tobacco industry stipulates that the ventilation rate standard rod should be checked regularly once a year.

The tobacco industry currently mainly uses soap film flowmeters to calibrate ventilation rate standards. Soap film flowmeters generally use human eye readings, which have the disadvantages of poor measurement repeatability and large random errors; soap film flowmeters need to measure the total flow rate of the ventilation rate standard rod and ventilation flow in two steps, and the work efficiency is low; soap film flowmeters It is a wet measurement method, and the soap film will wet the test air, which is inconsistent with the actual working condition of the ventilation rate standard rod. Therefore, it is necessary to develop a set of ventilation rate standard rod calibration device with strong reliability, high efficiency and high accuracy, and establish a corresponding ventilation rate standard rod calibration method.

Contents of the invention

Based on the deficiencies of the prior art, the object of the present invention is to provide an active double-piston ventilation rate standard rod calibration device and calibration method.

An active dual-piston ventilation rate standard rod calibration device, comprising a clamp for clamping the standard rod, a first piston mechanism, a second piston mechanism, a first differential pressure sensor, and a second differential pressure sensor, the two ends of the clamp A first air inlet and an air outlet are respectively provided, and a second air inlet is provided on its side, the first air inlet is connected with the outside world, the second air inlet is connected with the second piston mechanism, and the clamp The air outlet of the clamp is connected to the first piston mechanism, the first differential pressure sensor is connected between the air outlet of the clamp and the first piston mechanism, and the second differential pressure sensor is connected between the second piston mechanism and the second air inlet between mouths.

The first piston mechanism includes a first stepping motor, a first ball screw, a first guide groove, a first guide plate, a first piston rod, a first piston, a first cylinder and a first solenoid valve. The first stepper motor is fixed at the end of the first guide groove, and is connected with the first ball screw through a coupling, and the first ball screw is connected with the first guide plate through a first nut, and the first The piston rod is fixed on the first guide plate, the first piston is embedded in the first cylinder body, the first cylinder body is connected with the first guide groove, and the first solenoid valve is connected in series body and the air outlet of the fixture, the first differential pressure sensor is connected in parallel between the first cylinder and the air outlet of the fixture, and the second piston mechanism includes a second stepping motor, a second ball screw, a second Two guide slots, a second guide plate, a second piston rod, a second piston, a second cylinder and a second solenoid valve, the second solenoid valve is connected in series between the second cylinder and the second air inlet of the fixture Between, the second differential pressure sensor is connected in parallel between the second cylinder and the second air inlet of the fixture.

The standard rod is a cylindrical structure, which includes an air inlet end face, an air outlet end face, and a side end face. The total capillary hole inside the standard rod runs through between the air outlet end face and the air inlet end face, and the side end face is provided with a ventilation capillary hole near the air outlet end face. , The ventilation capillary hole is connected with the total capillary hole.

The accuracy grade of the ball screw is not lower than P5.

The solenoid valve is a two-position three-way type.

Both the first cylinder and the second cylinder are cylindrical with the same inner diameter, and the volumes of both are not less than 600mL.

A method for calibrating the ventilation rate of a standard rod, comprising the following steps:

S1: Install the standard rod into the fixture, the ventilation capillary hole corresponds to the second air inlet of the fixture, and the inner wall near the first air inlet of the fixture is sealed with the side end surface of the standard rod;

S2: Calibration, the first stepping motor rotates in the forward direction to drive the coupling and the first ball screw to rotate, the first ball screw cooperates with the first guide plate through the first nut, and the first guide plate drives the first piston rod , The first piston moves to the left, the air in the first cylinder becomes negative pressure, the first solenoid valve opens, the air flows through the standard rod, the first solenoid valve enters the first cylinder, and the first differential pressure sensor is used to measure The pressure drop of the standard rod; adjust the speed of the first stepping motor to make the air flow in the first cylinder be a constant flow, and the constant flow is 17.5mL/s.

Under the suction of constant flow, the ventilation capillary hole of the standard rod has air continuously flowing in, the second solenoid valve is opened, and the second cylinder becomes negative pressure. At this time, the second stepper motor is controlled to rotate in reverse to drive the coupling . The second ball screw rotates, and the second ball screw drives and cooperates with the second guide plate through the second nut. The second guide plate drives the second piston rod and the second piston to move upward, and the pressure in the second cylinder gradually rises. The second differential pressure sensor is used to monitor the pressure of the ventilation capillary hole in real time; when the indication value of the second differential pressure sensor is zero, it indicates that the running speed of the second piston is balanced with the air flow of the ventilation capillary hole; after the first piston runs at a constant speed , adjust the running speed of the second piston to make the indication value of the second differential pressure sensor zero. After running for a period of time t, record the running displacements of the first piston and the second piston respectively as s ₁ and s ₂ . The radii of the second cylinder are r ₁ and r ₂ respectively, the indication value of the first differential pressure sensor is P _D , and the atmospheric pressure is P;

The standard rod total flow is as follows,

The standard rod ventilation flow is as follows,

Assuming that the radii of the first cylinder and the second cylinder are equal, the value of the standard rod ventilation rate before correction is as follows,

The corrected standard rod ventilation rate values are as follows,

If the pressure drop introduced by the standard rod is not considered, the value of the ventilation rate of the standard rod is the ratio of the operating displacement s ₂ of the second piston to the operating displacement s ₁ of the first piston;

S3: After the calibration is completed, if the first piston and the second piston move to the limit position, the first solenoid valve and b24 are controlled to close and communicate with the atmosphere. The first piston moves to the right and the second piston moves downward to realize the calibration device reset.

Compared with the prior art, the present invention has the following beneficial effects: the present invention adopts a double-piston flow standard device driven by a stepping motor, the first piston and the second piston operate synchronously and in coordination, and the calibration of the ventilation rate standard rod can be realized, with reliable It has the advantages of strong performance, high efficiency and high accuracy.

Description of drawings

Fig. 1 is the structural representation of the embodiment of the present invention;

Fig. 2 is a schematic diagram of a standard rod structure of the present invention;

Fig. 3 is the enlarged schematic view of the standard bar section of the present invention;

In the figure: 1. The first stepping motor, 2. The first coupling, 3. The first ball screw, 4. The first nut, 5. The first guide plate, 6. The first guide groove, 7. The first A piston rod, 8, the first piston, 9, the first cylinder, 10, the first solenoid valve, 11, the first differential pressure sensor, 12, the fixture, 13, the standard rod, 14, the second differential pressure sensor, 15 , the second stepper motor, 16, the second coupling, 17, the second ball screw, 18, the second nut, 19, the second guide plate, 20, the second guide groove, 21, the second piston rod, 22, the second piston, 23, the second cylinder block, 24, the second solenoid valve, 25, the side end face, 26, the air outlet end face, 27, the air intake end face, 28, the total capillary hole, 29, the ventilation capillary hole.

Detailed ways

The implementation of the present invention will be illustrated by specific specific examples below, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

See Figure 1. The structures, proportions, sizes, etc. shown in the drawings attached to this specification are only used to cooperate with the content disclosed in the specification for the understanding and reading of those who are familiar with this technology, and are not used to limit the conditions for the implementation of the present invention. Therefore, there is no technical substantive meaning, and any modification of structure, change of proportional relationship or adjustment of size shall still fall within the scope of the disclosure of the present invention without affecting the functions and objectives of the present invention. within the scope of technical content. At the same time, terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit this specification. The practicable scope of the invention and the change or adjustment of its relative relationship shall also be regarded as the practicable scope of the present invention without any substantial change in the technical content.

As shown in Figure 1, an active double-piston ventilation rate standard bar calibration device includes a clamp 12 for clamping a standard bar 13, a first piston 8 mechanism, a second piston 22 mechanism, a first differential pressure sensor 11, a second Pressure difference sensor 14, the two ends of described fixture 12 are respectively provided with first air inlet 121 and air outlet, and its side is provided with second air inlet 122, and first air inlet 121 is connected with the outside world, and the second The air inlet 122 is connected to the second piston 22 mechanism, the gas outlet of the clamp 12 is connected to the first piston 8 mechanism, and the first differential pressure sensor 11 is connected to the gas outlet of the clamp 12 and the first piston 8 mechanism, the second differential pressure sensor 14 is connected between the second piston 22 mechanism and the second air inlet 122.

The first piston 8 mechanism includes a first stepping motor 1, a first ball screw 3, a first guide groove 6, a first guide plate 5, a first piston rod 7, a first piston 8, and a first cylinder 9 And the first electromagnetic valve 10, the first stepping motor 1 is fixed on the end of the first guide groove 6, and connected with the first ball screw 3 through the first coupling 2, the first ball screw 3 is connected with the first guide plate 5 through the first nut 4, the first piston rod 7 is fixed on the first guide plate 5, the first piston 8 is embedded in the first cylinder 9, the first The cylinder body 9 and the first guide groove 6 are connected back and forth, the first solenoid valve 10 is connected in series between the first cylinder body 9 and the air outlet of the fixture 12, and the first differential pressure sensor 11 is connected in parallel between the first cylinder body 9 and the Between the air outlets of the clamp 12, the second piston 22 mechanism includes a second stepper motor 15, a second ball screw 17, a second guide groove 20, a second guide plate 19, a second nut 18, a second piston Rod 21, second piston 22, second cylinder 23 and second solenoid valve 24, the second solenoid valve 24 is connected in series between the second cylinder 23 and the second air inlet 122 of clamp 12, the second The differential pressure sensor 14 is connected in parallel between the second cylinder 23 and the second air inlet 122 of the fixture 12 .

The standard rod 13 is inserted into the fixture 12, the first differential pressure sensor 11 is used to measure the pressure drop value of the standard rod 13, and the indication value of the second differential pressure sensor 14 is kept at zero during the operation of the calibration device .

As shown in Fig. 2 and Fig. 3, the standard rod 13 is a cylindrical structure, which includes an air inlet end face 27, an air outlet end face 26, and a side end face 25. The total capillary hole 28 inside the standard rod 13 runs through the air outlet end face 26 and the air inlet end face. Between the air end faces 27 , the side end face 25 is provided with a ventilation capillary hole 29 near the air outlet end face 26 , and the ventilation capillary hole 29 communicates with the total capillary hole 28 .

During the working process of the ventilation rate standard rod 13, the test air flows in from the ventilation capillary hole 29 and the air inlet end surface 27, and the two-way air flows out from the total capillary hole 28 of the air outlet end surface 26 after converging. The ratio of the air flow inflow of the ventilation capillary hole 29 to the air flow out of the total capillary hole 28 is the ventilation rate of the standard rod 13 . The ventilation rate of the standard rod 13 ranges from 0 to 100%, and the commonly used values are 20%, 50%, and 80%.

The accuracy grade of the ball screw is not lower than P5.

The solenoid valve is a two-position three-way type.

Both the first cylinder 9 and the second cylinder 23 are cylindrical with the same inner diameter, and the volumes of both are not less than 600mL.

A method for calibrating the ventilation rate of a standard rod, comprising the following steps:

S1: Install the standard rod 13 into the fixture 12, the ventilation capillary hole 29 corresponds to the second air inlet 122 of the fixture 12, and the inner wall at the first air inlet 121 of the fixture 12 is sealed with the side end surface 25 of the standard rod 13 ;

S2: Calibration, as shown in Figure 1, the first stepping motor 1 rotates forward to drive the first coupling 2 and the first ball screw 3 to rotate, and the first ball screw 3 connects with the first guide through the first nut 4 The plate 5 is driven and coordinated, the first guide plate 5 drives the first piston rod 7 and the first piston 8 to move to the left, the air in the first cylinder 9 becomes negative pressure, the first electromagnetic valve 10 is opened, and the air flows through the standard rod 13 , the first solenoid valve 10 enters in the first cylinder body 9, and the first differential pressure sensor 11 is used to measure the pressure drop of the standard rod 13; the rotating speed of the first stepping motor 1 is adjusted so that the air flow rate in the first cylinder body 9 is Constant flow, the constant flow is 17.5mL/s.

Under the suction of a constant flow rate, the ventilation capillary hole 29 of the standard rod 13 has air continuously flowing in, the second electromagnetic valve 24 is opened, and the inside of the second cylinder body 23 becomes negative pressure; at this time, the second stepper motor 15 is controlled to reverse The rotation drives the second shaft coupling and the second ball screw 17 to rotate, the second ball screw 17 is driven and matched with the second guide plate 19 through the second nut, and the second guide plate 19 drives the second piston rod 21, the second The piston 22 moves upwards, and the pressure in the second cylinder 23 gradually picks up, and the second differential pressure sensor 14 is used to monitor the pressure of the ventilation capillary hole 29 in real time; when the second differential pressure sensor 14 indicates zero, it indicates that the second piston 22 The operating speed is balanced with the air flow of the ventilation capillary hole 29; after the first piston 8 runs at a constant speed, adjust the operating speed of the second piston 22 so that the second differential pressure sensor 14 shows zero, and after running for a period of time, respectively Record the operating displacements of the first piston 8 and the second piston 22 as s ₁ and s ₂ , the radii of the first cylinder 9 and the second cylinder 23 as r ₁ and r ₂ respectively, and the indication value of the first differential pressure sensor 11 is P _D , and the atmospheric pressure is P;

The standard rod 13 total flow is as follows,

The standard stick 13 ventilation flow is as follows,

Assuming that the radii of the first cylinder 9 and the second cylinder 23 are equal, the ventilation rate value of the standard rod 13 before correction is as follows,

The corrected standard rod 13 ventilation rate values are as follows,

If the pressure drop introduced by the standard rod 13 is not considered, the ventilation rate value of the standard rod 13 is the ratio of the operating displacement s ₂ of the second piston 22 to the operating displacement s ₁ of the first piston 8;

S3: After the calibration is completed, if the first piston 8 and the second piston 22 move to the limit position, control the first solenoid valve 10 and b24 to close, communicate with the atmosphere, the first piston 8 moves to the right, and the second piston 22 goes down The movement enables resetting of the calibration device.

The calibration device adopts a double-piston flow standard device driven by a stepping motor. The first piston 8 and the second piston 22 operate synchronously and coordinately to realize the calibration of the ventilation rate standard rod 13. It has strong reliability, high efficiency and accuracy. Big plus.

The above-mentioned embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims (6)

1. An initiative double-piston ventilation rate standard stick calibrating device which characterized in that: the device comprises a clamp for clamping a standard rod, a first piston mechanism, a second piston mechanism, a first pressure difference sensor and a second pressure difference sensor, wherein a first air inlet and an air outlet are respectively arranged at two ends of the clamp, a second air inlet is arranged on the side surface of the clamp, the first air inlet is connected with the outside, the second air inlet is connected with the second piston mechanism, the air outlet of the clamp is connected with the first piston mechanism, the first pressure difference sensor is connected between the air outlet of the clamp and the first piston mechanism, and the second pressure difference sensor is connected between the second piston mechanism and the second air inlet;

the first piston mechanism comprises a first stepping motor, a first ball screw, a first guide groove, a first guide plate, a first piston rod, a first piston, a first cylinder body and a first electromagnetic valve, wherein the first stepping motor is fixed at the end part of the first guide groove and is connected with the first ball screw through a coupler, the first ball screw is connected with the first guide plate through a first nut, the first piston rod is fixed on the first guide plate, the first piston is embedded in the first cylinder body, the first cylinder body is connected with the first guide groove in a front-back manner, the first electromagnetic valve is connected between the first cylinder body and an air outlet of the clamp in series, the first differential pressure sensor is connected between the first cylinder body and the air outlet of the clamp in parallel, the second piston mechanism comprises a second stepping motor, a second ball screw, a second guide groove, a second guide plate, a second piston rod, a second cylinder body and a second electromagnetic valve, and a second electromagnetic valve are connected between the second cylinder body and a second air inlet of the clamp in series, and the second differential pressure sensor is connected between the second cylinder body and the second air inlet of the clamp in parallel;

the standard rod is of a cylindrical structure and comprises an air inlet end face, an air outlet end face and a side end face, a total capillary hole in the standard rod penetrates through the air outlet end face and the air inlet end face, a ventilation capillary hole is formed in the side end face, close to the air outlet end face, of the standard rod, and the ventilation capillary hole is communicated with the total capillary hole.

2. The active double-piston ventilation rate standard rod calibration device of claim 1, wherein: the ball screw accuracy level is not lower than P5.

3. The active double-piston ventilation rate standard rod calibration device of claim 1, wherein: the electromagnetic valve is of a two-position three-way type.

4. The active double-piston ventilation rate standard rod calibration device of claim 1, wherein: the first cylinder body and the second cylinder body are cylindrical, the inner diameters are the same, and the volumes of the first cylinder body and the second cylinder body are not smaller than 600mL.

5. A method of calibrating the ventilation rate of a standard rod based on the calibration device of any one of claims 1 to 4, comprising the steps of:

s1: installing the standard rod into a clamp, wherein the ventilation capillary hole corresponds to a second air inlet of the clamp, and the inner wall of the clamp close to the first air inlet is sealed with the side end surface of the standard rod;

s2: the calibration is carried out, the first stepping motor rotates forward to drive the coupler and the first ball screw to rotate, the first ball screw is in transmission fit with the first guide plate through the first nut, the first guide plate drives the first piston rod and the first piston to move leftwards, air in the first cylinder body becomes negative pressure, the first electromagnetic valve is opened, atmospheric air enters the first cylinder body through the standard rod and the first electromagnetic valve, and the first differential pressure sensor is used for measuring the pressure drop of the standard rod; the rotating speed of the first stepping motor is regulated to enable air flow in the first cylinder body to be constant, under the suction of the constant flow, air continuously flows into the ventilation capillary hole of the standard rod, the second electromagnetic valve is opened, the second cylinder body is changed into negative pressure, at the moment, the second stepping motor is controlled to reversely rotate to drive the coupler and the second ball screw to rotate, the second ball screw is in transmission fit with the second guide plate through the second nut, the second guide plate drives the second piston rod and the second piston to move upwards, the pressure in the second cylinder body gradually rises, and the second differential pressure sensor is used for monitoring the pressure of the ventilation capillary hole in real time; when the second differential pressure sensor indicates zero, indicating that the operating speed of the second piston is balanced with the ventilation capillary bore air flow; after the first piston runs at a constant speed, the running speed of the second piston is regulated to enable the indication value of the second differential pressure sensor to be zero, after a period of running time t, running displacements of the first piston and the second piston are respectively recorded as s1 and s2, the radiuses of the first cylinder body and the second cylinder body are respectively r1 and r2, and the indication value of the first differential pressure sensor is P _D The atmospheric pressure is P; the total flow rate of the standard rod is as follows,

the standard rod ventilation flow rate is as follows,

assuming equal radii of the first cylinder and the second cylinder, the standard rod ventilation values before correction are as follows,

the corrected standard rod ventilation values are as follows,

if the pressure drop introduced by the standard rod is not considered, the ventilation value of the standard rod is the ratio of the second piston operation displacement s2 to the first piston operation displacement s 1;

s3: after calibration is completed, if the first piston and the second piston are operated to the vicinity of the limit position, the first electromagnetic valve and the b24 are controlled to be closed and communicated with the atmosphere, and the first piston moves rightwards and the second piston moves downwards so as to reset the calibration device.

6. The method for calibrating ventilation rate of standard rod according to claim 5, wherein: the constant flow rate described in S2 was 17.5mL/S.